new Civic or used A4 1.8T

Hi, next year I'll go to study master degree in USA.
Dad give me a budget of $18,000 for a car. Should it
be brand new Civic or used nice A4 1.8T ?
I'm not sure the price of 1 year old A4 1.8T, can I find
one at $18k ?
Thanks
K.Ben